Tablets and other objects are film coated by including in the tablet a film-forming polymer that is activated upon contact with an activating amount of liquid. The marker is disposed in a hole on a biodegradable structural element of the stent, and the marker and the hole have substantially the same configuration. At least a portion of the multimedia content may be communicated via at least one of the plurality of downlink communication paths to at least one mobile communication device based on at least the determined at least the BER. When a back pressure of the water flow is larger than an atmospheric pressure outside, the valve plate is forced to close the air intake hole, so as to avoid leakage of the water flow and prevent the air intake hole from being clogged by impurities. An alternative embodiment of the plug assembly has conductive contacts that are brought into contact with the tip and ring contacts of the jack when the cover is closed.